In the past, much effort has been expended in preparing thermally stable polycarbonate compositions which would be color stable at elevated temperatures and particularly at the high molding temperatures generally employed to prepare molded polycarbonate articles. Many different additives have been found that are quite suitable for rendering polycarbonates heat and color stable. Particularly useful are triorgano phosphites such as are disclosed in U.S. Pat. No. 3,305,520. In addition, U.S. Pat. Nos. 3,729,440 and 3,953,388 disclose thermally stable aromatic polycarbonates containing a phosphinite and an epoxy compound. Further, U.S. Pat. No. 3,794,629 discloses chemically stable aromatic polycarbonates containing oxetane phosphites and U.S. Pat. No. 3,978,020 discloses thermally stable aromatic polycarbonates containing phosphonites which include epoxy compounds.
Polycarbonates are also used for producing bottles; however, these bottles become hazy after sterilization in water or exposure to moisture at elevated temperatures. U.S. Pat. No. 3,839,247 discloses a water clear polycarbonate composition which can be used to mold bottles wherein the polycarbonate composition contains an aromatic epoxy or an aliphatic epoxy compound as a stabilizer.
Copending application Ser. No. 957,426, filed Nov. 2, 1978, now issued as U.S. Pat. No. 4,247,448, discloses the use of phosphonite oxetanes with aromatic polycarbonates, copending application Ser. No. 957,429, filed Nov. 2, 1978, now abandoned, discloses the use of hindered phenol phosphite oxetanes, copending application Ser. No. 957,428, filed Nov. 2, 1978, discloses the use of hindered phenol phosphonite oxetanes, and copending application Ser. No. 957,430, filed Nov. 2, 1978, discloses the use of hindered phenol phosphites all with aromatic polycarbonate, all of these copending applications being assigned to the same assignee as this case.